criminality correlates with lead exposure

Provocative results, reported in New Scientist:

Now Kim Dietrich at the University of Cincinnati College of Medicine and his colleagues have looked prospectively at how lead levels affect the risk of being arrested in adulthood. They recruited 250 pregnant women from a poor lead-contaminated inner-city district in Cincinnati.

The researchers took blood samples from the women early in pregnancy, then sampled the blood of the children four times a year till age 5, and then twice a year until they were about 7 years old.
Increased arrests

Years later, the researchers checked public records to see if their subjects had been arrested since reaching the age of 18, and if so, how many times and for what. Independent reviewers coded them into categories, such as violent offences, drug offences and fraud.

After controlling for factors including maternal IQ, maternal arrest rates, parenting style and socioeconomic factors, they found that prenatal and childhood lead concentrations in the blood predicted likelihood of adult arrest.

A 5 microgram/decilitre increment in average childhood blood lead level, for instance, increased the rate of arrest for violent crimes by 26%. And high prenatal blood levels predicted the total number of adult arrests.

Results tentative, subject to further clarification or potential retraction. I'd be curious to know how those other factors compared in predictive power.